Earth anchor method and apparatus

ABSTRACT

An improved earth anchor includes modifications allowing it to be driven more accurately into hard or clay-rich soil. Methods of manufacture, use, and devices are described.

FIELD OF THE INVENTION

Specific embodiments relate to apparatus and methods of use and manufacture related to earth anchor systems.

BACKGROUND

The discussion of any work, publications, sales, or activity anywhere in this submission, including in any documents submitted with this application, shall not be taken as an admission that any such work constitutes prior art. The discussion of any activity, work, or publication herein is not an admission that such activity, work, or publication existed or was known in any particular jurisdiction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a photo illustrating a prior art Arrowhead Earth Anchor bent off end of drive bar due to lateral forces.

FIG. 2 is a diagram illustrating an arrowhead (blue) with attached sheath (red) to accept the drive bar (black) as viewed laterally a), and on edge b). The arrowhead is allowed to pivot through small angles about the point of contact at the end of the drive bar. When the arrowhead becomes unaligned with the drive bar, c), the resulting lateral force above the pivot point stabilizes the alignment while the lateral force below the pivot point further destabilizes the alignment.

FIG. 3 is a diagram illustrating that moving the pivot point down closer to the point of the arrowhead increases the area of stabilizing lateral force according to specific embodiments.

FIG. 4 are photographs illustrating an improved earth anchor that allows the drive bar to make contact closer to the tip according to specific embodiments. (c) illustrates that the end of the drive bar is notched in the middle to assure the arrowhead pivots about the point of contact, and the walls are tapered in a rotation to facilitate retrieval of the bar by twisting.

FIG. 5 is a photograph illustrating an improved anchor with a split drive bar to allow the arrowhead to be guided from the front of the triangle even if it is driven from the point of contact in the back according to specific embodiments.

FIG. 6 is a diagram illustrating an embodiment wherein a length of the drive bar is left with the arrowhead in order to increase the barrier to rotation according to specific embodiments. a) The arrowhead is driven downward by a drive bar dragging the cable. b) The drive bar is retrieved. c) Application of tension on the cable deforms the arrowhead both at the point of attachment of the cable, as well as the fins by the downward force of the earth.

DESCRIPTION OF SPECIFIC EMBODIMENTS

According to specific embodiments, the present invention is involved with methods and/or systems and/or devices that can be used together or independently to provide improved anchoring systems. This description introduces a selection of concepts that are further described or can be further understood from consideration of the drawings and the example apparatus described herein. Key features or essential features of the claimed subject matter are discussed throughout this submission, thus no individual part of this submission is intended to determine the scope of the claimed subject matter.

The general structure and techniques, and more specific embodiments that can be used to effect different ways of carrying out the more general goals are described herein. Although only a few embodiments have been disclosed in detail herein, other embodiments are possible and the inventor(s) intend these to be encompassed within this specification. The specification describes specific examples to accomplish a more general goal that may be accomplished in another way. This disclosure is intended to be exemplary, and the claims are intended to cover any modification or alternative that might be predictable to a person having ordinary skill in the art.

The inventors intend that only those claims which use the words “means for” are intended to be interpreted under 35 U.S.C. § 112, sixth paragraph. Moreover, no limitations from the specification are intended to be read into any claims, unless those limitations are expressly included in the claims. Particular materials described herein are for example purposes only, and any suitable materials can be used to achieve the apparatus.

Where a specific numerical value is mentioned herein, it should be considered that the value may be increased or decreased by 20%, while still staying within the teachings of the present application, unless some different range is specifically mentioned. Where a specified logical sense is used, the opposite logical sense is also intended to be encompassed.

Commonly used earth anchors, such as the Arrowhead Earth Anchors™ used by American Earth Anchor™, (e.g., the Galvanized Steel and Aluminum Mil-Spec) are generally driven from the back by a drive bar, usually by compressive blows from a sledge- or jackhammer. This makes for an unstable transit through the earth that is sometimes problematic in heavier or clay-rich soil. The movement of the arrowhead through earth is similar to a triangle flying through the air or being pushed through water. When the arrowhead is not perfectly aligned, the resulting lateral forces push the arrowhead more out of alignment. The continued increase in lateral force can complicate driving the arrowhead and even bend the arrowhead off the end of the bar. FIG. 1 is a photo illustrating a prior art Arrowhead Earth Anchor bent off end of drive bar due to lateral forces.

FIG. 2 is a diagram illustrating an arrowhead (blue) with attached sheath (red) to accept the drive bar (black) as viewed laterally a), and on edge b). The arrowhead is allowed to pivot through small angles about the point of contact at the end of the drive bar. When the arrowhead becomes unaligned with the drive bar, c), the resulting lateral force above the pivot point stabilizes the alignment while the lateral force below the pivot point further destabilizes the alignment. The arrowhead is allowed to pivot through small angles about the point of contact at the end of the drive bar. When the arrowhead becomes unaligned with the drive bar, c), the resulting lateral force above the pivot point stabilizes the alignment while the lateral force below the pivot point further destabilizes the alignment. FIG. 2 illustrates how the lateral force on the arrowhead can stabilize or destabilize a misalignment depending when whether the force is above or below the pivot point. Generally, statements and drawings herein can be understood with the earth anchor pointed generally downward.

First Example Embodiment

According to specific embodiments, it is determined that the alignment of the arrowhead is more stable if there is more area above the pivot point (e.g., as shown in FIG. 3). It is further determined that the criterion for stability is the pivot point should be below the center of mass of the two-dimensional shape of the arrowhead. For a triangle, this would be ⅓ of the way from the base to the bottom point. In the example prior art anchors above, the pivot point for the arrowheads is less than ⅓ the way to the bottom point, so the arrowheads are unstable. Specific innovative embodiments are provided herein to stabilize the earth anchors and otherwise improve the performance of the earth anchors.

Example Modification 1: One embodiment provides an earth anchor wherein the pivot point is moved toward the tip by moving the point of contact toward the tip. FIG. 3 shows how moving the point of contact closer to the point of the arrowhead increases the area of stabilizing force and decreases the area of destabilizing force. If the point of contact is further than ⅓ of the way down from the base of the triangle, the alignment of the triangle should be stable.

One example of accomplishing this can be understood as follows. FIG. 1 shows that the present arrowhead is loosely attached to the drive bar by means of three steel bands pressed from the same steel piece as the arrow itself. By pressing another band of steel closer to the tip (e.g., as shown in FIG. 4), the bar would contact the arrowhead further toward the tip, and importantly below the ⅓ distance from the base of the triangle. It is important that the steel bands around the bar be loose enough to allow the arrowhead to pivot through small angular deflections about the point of contact. Another way to achieve stability is to elongate the fins of the arrowhead or the sheath of the arrowhead upward along the length of the drive bar. This would have the same effect of placing the point of contact below the two dimensional center of mass by moving the arrowhead's center of mass upward.

An optional improvement to facilitate driving the arrowhead as well as retrieval of the drive bar is shown in FIG. 4 c. The drive bar can be notched in the middle to force the point of contact to be the pivot point. Rotation of the drive bar in the correct direction should dislodge the drive bar from the arrowhead.

Example Embodiment 2

Modification 2: Move the pivot point toward the tip by clamping the Arrowhead into the split drive bar. FIG. 5 shows how the pivot point can be moved toward the tip by splitting the drive bar such that the arrowhead is bound firmly near the top point but have some lateral space at the point of contact. According to specific embodiments, it is important that the arrowhead be allowed to move slightly at the original (in FIG. 2) point of contact allowing the point closest to the tip to be the pivot point. It is also important that the steel bands around the bar be loose enough to allow the arrowhead to pivot through small angular deflections.

Example Embodiment 3

Modification 3: Increase the pullout force by elongating arrowhead. The pullout force may be increased by restricting the arrowhead from turning around after insertion. This could be done by one of three methods: extending the collar (sheath) further up the length of the drive bar, having part of the drive bar detach with the arrowhead (FIG. 6), or making the arrowhead and sheath longer. Additionally, a longer, thinner arrowhead with the cable connected close to the center of mass, but slightly closer to the tip, would have the same lateral surface against pulling out, but have greater resistance to turning around and have less resistance to being driven into the earth, facilitating insertion.

Prototype Testing

In examples of testing of the above embodiments, modification 2 allowed the arrowhead to be driven to the depth desired (about 6′) even in clay-rich earth and modification 1 also improved performance. Modification 3 was conceived following two failed attempts to retrieve the drive bar using Modification 2. In specific embodiments, the deformation during insertion prevented the drive bar from being pulled out. Tensile force on the bar during efforts to retrieve the bar likely further deformed the arrowhead as in FIG. 6 c. The drive bar was subsequently sawed off at the ground and the attached cable seems to demonstrate considerably higher pullout force than cables attached to arrowheads alone. 

What is claimed:
 1. An earth anchor apparatus configured to be driven through a material by a force applied to a drive bar operationally connected thereto comprising a pivot point between the drive bar and the earth anchor that is closer to the penetrating terminus or point of the earth anchor than is the center of mass of the two-dimensional projection of the shape of the earth anchor.
 2. The apparatus of claim 1 where the proximity of the pivot point to the terminus of the earth anchor is achieved by placing the point of contact between the drive bar and the earth anchor closer to the terminus of the earth anchor.
 3. The apparatus of claim 2 where the drive bar is machined at the point of contact to have a depression in the middle and/or rotationally tapered sides resulting in a dislodging force upon rotating the drive bar in the correct direction.
 4. The apparatus of claim 1 wherein the proximity of the pivot point to the terminus of the earth anchor is achieved by allowing the point of contact between the drive bar and the earth anchor to slide laterally while fixing an extension of the drive bar closer to the terminus of the earth anchor.
 5. The apparatus of claim 4 wherein the area below and near the point of contact is heavier and/or reinforced.
 6. The apparatus of claim 1 wherein the shape of the earth anchor is longer and thinner than that of an equilateral triangle.
 7. The apparatus of claim 6 wherein the earth anchor is reinforced near the point of contact and point of cable connection.
 8. An earth anchor apparatus configured to be driven through a material by a force applied to a drive bar operationally connected thereto comprising an earth anchor with increased length thereby increasing the activation barrier to rotation after being driven into the material with the cable under tension.
 9. The apparatus of claim 8 wherein the proximity of the pivot point to the terminus of the earth anchor is achieved by allowing the point of contact between the drive bar and the earth anchor to slide laterally while fixing an extension of the drive bar closer to the terminus of the earth anchor.
 10. The apparatus of claim 8 wherein the length of the arrowhead is increased through being attached to the drive bar, where the drive bar or a section of the drive bar is left in the earth.
 11. The apparatus of claim 10 wherein some rotation is allowed between the arrowhead and the section of drive bar attached to the arrowhead remaining in the ground with the arrowhead.
 12. An earth anchor apparatus comprising: an earth anchor body having a penetrating terminus for driving into a material; at least one lateral portion providing stability during penetration; and a point of contact for a driver that is closer to the penetrating terminus than the center of mass of the two-dimensional projection of the earth anchor body.
 13. The apparatus of claim 12 wherein the earth anchor body is configured to be driven through a material by a force applied to a drive bar operationally connected thereto comprising a pivot point between the drive bar and the earth anchor.
 14. The apparatus of claim 12 wherein the proximity of the pivot point to the terminus of the earth anchor is achieved by placing the point of contact between the drive bar and the earth anchor closer to the terminus of the earth anchor.
 15. The apparatus of claim 12 wherein the drive bar is machined at the point of contact to have a depression in the middle and/or rotationally tapered sides resulting in a dislodging force upon rotating the drive bar in the correct direction.
 16. The apparatus of claim 12 wherein the proximity of the pivot point to the terminus of the earth anchor is achieved by allowing the point of contact between the drive bar and the earth anchor to slide laterally while fixing an extension of the drive bar closer to the terminus of the earth anchor.
 17. The apparatus of claim 12 wherein the shape of the earth anchor is longer and thinner than that of an equilateral triangle.
 18. The apparatus of claim 12 wherein the earth anchor is reinforced near the point of contact and a point of cable connection.
 19. The apparatus of claim 12 further wherein the earth anchor is configured to be driven through a material by a force applied to a drive bar operationally connected thereto comprising an earth anchor with increased length thereby increasing the activation barrier to rotation after being driven into the material with the cable under tension.
 20. The apparatus of claim 19 wherein the proximity of the pivot point to the terminus of the earth anchor is achieved by allowing the point of contact between the drive bar and the earth anchor to slide laterally while fixing an extension of the drive bar closer to the terminus of the earth anchor. 